Light piping unit for supplying radiant energy to the interior of a pressure vessel

ABSTRACT

A light piping unit for use in supplying radiant energy to the interior of a pressure vessel having an internal operating pressure differing from ambient pressure external to the vessel. The unit includes an elongated optical light pipe formed intermediate its ends with an integral frusto-conically shaped mounting surface. The light pipe extends through an aperture in the wall of the pressure vessel with the mounting surface thereof in fluid sealed engagement with a cooperating frusto-conically shaped mounting surface defined in a mounting fixture attached to the vessel. The mounting surfaces of the light pipe and fixture are maintained in pressure-fluid sealing engagement with each other by the difference between the vessel operating and the ambient pressures acting on the inner and outer ends of the light pipe. A radiant energy source is accurately supported in proximity to an essentially conically shaped outer end of the light pipe either directly by the light pipe or by the mounting fixture.

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United States Patent Canty 1 May 28, 1974 flL LIGHT PIPING UNIT FORSUPPLYING RADIANT ENERGY TO THE INTERIOR OF A PRESSURE VESSEL Inventor:John M. Canty, 117 Cornwell Ave., Tonawanda, NY. 14150 Filed: Oct. 16,1972 Appl. N0.: 297,801

US. Cl 219/354, 219/338, 219/347, 219/357, 240/1 LP, 250/227, 350/96 RInt. Cl. H05b l/00, GOZb 5/14 Field of Search 219/347, 354, 553, 342,219/357, 338, 411; 240/1 El,'l LP, 10 L,

References Cited UNITED STATES PATENTS 9/1951 Shannon 350/96 R 3/1957Haynes et al. 240/1 EL 78 6/1959 8/1966 24 11/1966 70 l/1967 6/1971Haggstrom. Kawecki Witt et al.

Primary Examiner-A. Bartis Attorney, Agent, or Firm-Bean & Bean 1 57]ABSTRACT A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel. The unitincludes an elongated optical light pipe formed intermediate its endswith an integral frusto-conically shaped mounting surface. The

light pipe extends through an aperture in the wall of the pressurevessel with the mounting surface thereof in fluid sealed engagement witha cooperating frustoconically shaped mounting surface defined in amounting fixture attached to the vessel. The mounting surfaces of thelight pipe and fixture are maintained in pressure-fluid sealingengagement with each other by the difference between the vesseloperating and the ambient pressures acting on the inner and outer endsof the light pipe. A radiant energy source is accurately.

supported in proximity to an essentially conically shaped outer end ofthe light pipe either directly by the light pipe or by the mountingfixture.

13 Claims, 7 Drawing Figures I PATENIEDmza m4 SHEET 2 BF 2 Fig. 6.

LIGHT PIPING UNIT FOR SUPPLYING RADIANT ENERGY TO THE INTERIOR OF APRESSURE VESSEL SUMMARY OF THE INVENTION The present invention broadlyrelates to the utilization of so-called fiber optic material, such asacrylic plastic, for transmitting radiant energy in the form of lightand/or heat from an external source into a pressure vessel, particularlywhere vessel environment is hostile to electrical wiring and/or thevessel has a limited amount of usable internal space. More particularly,the invention relates'to a compact, readily inof the light pipe or on alight pipe enclosing tube car ried by the mounting fixture.

In a preferred form of the present invention, the light pipe andmounting fixture are formed with frustoconically shaped mountingsurfaces, which are maintained in pressure-fluid sealing engagement bythe difference between ambient or atmospheric and vessel pressureconditions. For installations wherein there exists only slightdifferences between ambient and vessel pressures and/or when the vesselpressure conditions are variable the fixture may be provided withadditional devices for positively maintaining the light pipe properlyseated in pressure-fluid sealed relationship therewith.

DRAWINGS The nature and mode of the present invention will now be morefully described in the following detailed description taken with theaccompanying drawings wherein:

FIG. I is a side view ofthe light piping unit of the present inventionwith parts broken away for purposes of clarity;

FIG. 2 is an enlarged view of the light pipe illustrated in FIG. 1;

FIG. 3 is a fragmentary sectional view of an alternative form of thelightpiping unit adapted for use with vacuum vessels;

FIG. 4 is a fragmentary sectional view of an other alternative form ofthe light piping unit adapted for use with pressurized vessels; and

FIGS. 5 through 7 are fragmentary sectional views illustratingmodifications of the unit of FIG. 4.

DETAILED DESCRIPTION Reference is now made particularly to FIG. 1,wherein the light piping unit of the present invention is generallydesignated as'l0 and shown as including an elongated light pipe 12having an essentially circular cross-sectional configuration; a fixture14 for mounting light pipe 12 in pressure-fluid sealed relationshipwithin an aperture 16 formed in the wall 18 of a pressure vessel; and aunit 20 for defining a source of radiant energy in the form of lightand/or heat.

Light pipe 12 is best shown in FIGS. 1 and 2 as having an inner ordiffuser end portion 22 having a suitably configured radiant energyoutlet surface 24; an inter-. mediate portion 26, which is stepped todefine an integrally formed annular mounting surface 28; and an outer.end portion 30, which is formed with a suitably configured radiantenergy entrance face or surface 32. Light'pipe 12 may be of any suitablefiber optic material, such as cast acrylic plastic.

Mounting fixture 14 is of two partconstruction including a first part inthe form of an internally threaded outer sleeve 34, which is suitablyfixed in a pressurefluid sealed relationship to the outer surface ofwall 18 concentrically of aperture 16, as by welding; and a second partin the form of an internally threaded inner sleeve 36, which isthreadably received by sleeve 34 having its through opening stepped todefine an annular mounting surface 38, as shown in FIG. 1. As will beapparent, sleeves 34 and 36 cooperate to define an opening 39, which isaligned with aperture 16 and adapted to removably receive light pipe 12.Preferably, mounting surfaces 28 and 38 are complimentary and are offrusto-conical configuration and have like cone angles on the order ofabout 45. In the arrangement shown vessel pressure in excess of ambientor atmospheric pressure is employed to force mounting surface 28 intopressure-fluid sealing engagement with mounting surface 38, and therebymaintain light pipe' 12 seated relative to mounting fixture 14. Thus, inthis arrangement, surface 28 faces towards outer end portion 30 andsurface 38 faces towards vessel 18. It is convenient to pro videmounting fixture 14 with a set screw or like device 40 in order tofacilitate assembly of the unit and to prevent displacement of themounting surfaces when pressure within the vessel is reducedto ambientcondition.

Unit 20 is shown in FIG. I as including a housing 42, which serves toenclose a radiant energy source in the form of an electric light bulb44, a light bulb associated reflector 46 and a holder device 48 adaptedto removably mount a heat filter plate 50 permeable to light rays. Whenfilter 50 is removed, heat as well as light from bulb 44 is applied toinlet surface 32 and transmitted by the light pipe into the pressurevessel.

. In a preferred form of the present invention, housing 42 is removablyfixed to the outer end of light pipe by a conventional tube couplingdevice 51, which includes a shouldered compression sleeve 52, nuts 54and 56 and a deformable clamping sleeve 57. As will be apparent, sleeve52 is slideably fitted onto endportion 30, nut 54 is threaded ontosleeve 52 for the purpose of clamping a housing wall portion 42atherebetween and nut 56 is threaded onto sleeve 52 for the purpose ofdeforming sleeve 57 into friction grippingengagement with the outersurface of the light pipe.

In situations where it is desired to project a concentrated beam oflight into the pressure vessel, inlet surface 32 and outlet surface 24may be relatively flat. However, where it is desired to diffuse ordirect light into all cornersof the pressure vessel, I prefer to employthe essentially conically shaped inlet surface and thehemispherically-shaped outlet surface configuration illustrated in thedrawings, wherein the inlet surface is spaced from reflector 46 such asto position the latters focal point within the body of the light pipe atthe point generally designated as F.P." Outlet surface 24 may beroughened, as by sand blasting, to achieve maximum light dispersion.The'cone angle d) of surface 32 is determined by the equation (it 6 B,wherein B sin (sina/m), a (r11 (it) and critical angle 6 sin (1/n,-).Since III is known as being the cone angle for a given reflector 46, andn, is the known index of refraction of the light pipe, d) can be readilydetermined.

Coupling device 51 is provided with a suitable stop, such as a tab 58suitably fixed to the outer end surface of sleeve 52, for the purpose ofabutting against a marginal edge portion of surface 32 in order toinsure accurate positioning of light bulb 44 and associated reflector 46relative to such surface. This construction permits unit to be removedfor maintenance and then repositioned on the light pipe without need foradjustment of the spacing between the parts.

FIG. 3 illustrates an alternative form of the present invention, whichis particularly adapted for use with pressure vessels subject to vacuumoperating conditions. In this construction, light pipe 120 and mountingfixture 14a are identical to those discussed with reference to FIG. 1,except that surfaces 28a and 38a are reversed, whereby to permit ambientair pressure to maintain a pressure-fluid seal between such mountingsurfaces.

FIG. 4 illustrates an alternative construction wherein a two-partmounting fixture 14b is mounted inwardly of the vessel and includes afirst part in the form of a sleevelikebracket 60, which is suitablyfixed ina pressure-fluid sealed relationship to the inner surface ofwall 18 concentrically of aperture 16, as by welding;

and a second part in the form of a mounting ring 62,

which is releasably clamped to bracket 60, as by threaded bolt devices64, for the purpose of positively forcing light pipe mounting surface28b into engagement with the fixture mounting surface 38b defined inthis case by bracket 60. In this construction, the distance betweenmounting surface 28b and the light pipe outlet surface 24b issubstantially shortened and the diameter of inner end 22b reduced todefine: a shoulder 66 against which a deformable O-ring seal 68 isforced to bear by ring 62. This construction also differs from thatdescribed above with reference to FIG. 1, in that unit 20 is carried bythe outer end of a light pipe protecting shielding tube 70, which isarranged concentrically outwardly of light pipe 12!) and has its innerend weld affixed to bracket 60; and stop 58)) is formed integrally withsleeve 52 and arranged to abut against the outer end'of tube 70.

The embodiments illustrated in FIGS. 5 and 6 are quite similar to thatdescribed with reference to FIG. 4, except that brackets 60a and 60b areformed with recesses 72a and 72b to receive additional O-ring seals 74aand 74b, which are adapted to seal against light pipes 120 and 12d,respectively.

The construction shown in FIG. 7 differs from that illustrated in FIG. 4in that bracket 600 is removably affixed to the inner surface of wall 18by bolt fasteners 80, and is provided with an annular slot 82 adapted toreceive an O-ring 84.

I claim:

1. A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombinatron:

a fixture attached in pressure-fluid sealed relationship relative tosaid vessel wall peripherally of said wall aperture, said fixture havingan opening extending therethrough in alignment with said wall apertureand said fixture opening defining an annular mounting surface;

a light pipe formed of a fiber optic material, said light pipe beingarranged to extend through said fixture opening and having an inner endportion arranged inwardly of said vessel to define a radiant energyoutlet surface, an outer end portion arranged outwardly of said vesselto define a radiant energy entrance surface and an annular integrallyformed mounting surface complementary to said fixture mounting surfaceand maintained in pressure-fluid sealing engagement with said fixturemounting surface by the difference between said vessel operating andambient pressures acting on said inner and outer end portions;

a radiant energy source unit; and

mounting means for removably supporting said source unit outwardly ofsaid vessel on one of said fixture and said outer end portion of saidlight pipe whereby to apply radiant energy to said light pipe entrancesurface for transfer into said vessel through said light pipe.

2. A unit according to claim 1, wherein said mounting surfaces are offrusto-conical configuration and have like cone angles.

3. A unit according to claim 2, wherein each of said cone angles isapproximately 45.

4. A unit according to claim 1, wherein said source unit includes ahousing carrying an electric light bulb and a reflector for directingradiant energy from said bulb onto said light pipe entrance surface, andsaid mounting means releasably clamping said housing to said outer endportion of said light pipe and including stop means engageable with saidlight pipe entrance surface to position said bulb and said reflector ata predetermined distance from said light pipe entrance surface.

5. A unit according to claim 4, wherein said fixture includes an outersleeve affixed to an outer surface of said vessel wall and an innersleeve threadably affixed to said outer sleeve and defining said fixturemounting surface.

6. A unit according to claim 1, wherein a tube is carried by saidfixture concentrically outwardly of said light pipe, said source unitincludes a housing for carrying an electric light bulb and a reflectorfor directing radiant energy from said bulb onto said light pipeentrance surface, and said mounting .means releasably clamping saidhousing onto an outer end of said tube and including stop meansengageable with said outer end of said tube to position said bulb andsaid reflector at a predetermined distance from said light pipe entrancesurface.

7. A unit according to claim 6, wherein said fixture includes a firstpart fixed to an inner surface of said vessel wall and defining saidbounding surface thereof, and

a second part removably fixed to said first part for engagement withsaid inner end portion of said light pipe for positively maintainingsaid mounting surfaces seated in engagement, and an inner end of saidtube extends inwardly through said wall aperture and is affixed to saidfirst part.

8. A unit according to claim 7, wherein said inner end portion of saidlight pipe is formed with an annular shoulder intermediate said mountingsurface and said light pipe outlet surface, and a deformable sealingdevice is clampingly secured against said shoulder by said second part.

9. A unit according to claim 1, wherein said source unit includes ahousing carrying an electric light bulb and a reflector for directinglight from said bulb onto said light pipe entrance surface, said lightpipe entrance surface is essentially of conically shaped configurationhaving an apex portion thereof extending towards said bulb, and saidmounting means includes stop means cooperating with one of said fixtureand said light pipe for positioning said bulb and reflector at apredetermined distance from said light pipe entrance surface.

10. A light piping unit for use in supplying radiant en ergy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombination:

a fixture attached to said vessel wall peripherally of I said wallaperture, said fixture having an opening extending therethrough inalignment with said wall aperture;

a radiant energy source unit, said unit including a housing carrying anelectric light bulb and a reflector for directing radiant energy fromsaid bulb;

a light pipe fixed within said fixture opening, said light pipe havingan outer end portion defining a radiant energy entrance surface and aninner end portion defining a radiant energy outlet surface; and

mounting means for removably mounting said housing on said outer endportion of said light pipe, said mounting means including stop meansengageable with said light pipe entrance surface to position said bulband said reflector at a predetermined distance from said light pipeentrance surface.

11. A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombinatron:

a fixture attached in pressure-fluid sealed relationship relative tosaid vessel wall peripherally of said wall aperture, said fixture havingan opening extending therethrough in alignment with said aperture, andsaid fixture opening being stepped to define an annular mountingsurface;

a light pipe supported within said fixture opening, said light pipehaving an outer end portion defining a radiant energy entrance surfaceand an inner end portion defining a radiant energy outlet surface and anintermediate portion stepped to define an integrally formed annularmounting surface facing towards and being complementary to andmaintainedin pressure-fluid sealing engagement with said fixture mounting surfaceby the difference between said vessel operating and ambient pressuresacting on said inner and outer. end portions;

a radiant energy source unit; and

mounting means for removably supporting said source unitoutwardly ofsaid vessel on one of said fixture and said outer end portion of saidlight pipe whereby to apply radiant energy to said light entrancesurface for transfer into said vessel through said light pipe.

12. A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressure inexcess of ambient pressure external to the vessel, said vessel having anaperture formed in a wall thereof, which comprises in combina tion: v

a fixture having outer and inner sleeves, said outer sleeve beingattached in pressure-fluid sealed relationship relative to said vesselwall peripherally of said wall aperture, said inner sleeve beingthreadably connected to said outer sleeve and having a through openingarranged in alignment with said vessel opening, said inner sleeveopening being stepped to define an annular mounting surface facingtowards said vessel;

a light pipe supported within said inner sleeve opening and having anintegrally formed annular mounting surface complementaryto and disposedin pressure-fluid sealed engagement with said inner sleeve annularmounting surface, said light pipe having an outer end portion defining aradiant energy entrance surface and an inner end portion defining aradiant energy outlet surface;

a radiant energy source unit; and

mounting means for removably supporting said source unit outwardly ofsaid vessel on one of said fixture and said outer end portion of saidlight pipe whereby to apply radiant energy to said light pipe entrancesurface for transfer into said vessel through said light pipe.

13. A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombinatron:

a fixture having outer and inner sleeves, said outer sleeve beingattached in pressure-fluid sealed relationship relative to said vesselwall peripherally of said wall aperture, said inner sleeve beingthreadably connected to said outer sleeve and having a through openingarranged in alignment with said vessel opening, said inner sleeveopening being stepped to define an annular mounting surface;

a light pipe supported within said inner sleeve opening and having anannular mounting surface disposed in pressure-fluid sealed engagementwith said inner sleeve annular mounting surface, said light pipe havingan outer end portion defining a radiant energy entrance surface and aninner end portion defining a radiant energy outlet surface;

a radiant energy source unit, said source unit includes a housingcarrying an electric light bulb and a reflector for directing radiantenergy; and

mounting means for removably supporting said source unit outwardly ofsaid vessel on said light pipe whereby to direct radiant energy to saidlight pipe entrance surface for transfer into said vessel through saidlightpipe, said mounting means re- ]easably clamping said housing tosaid outer end portion of said light pipe and including stop meansengageable with said light pipe entrance surface to position said bulband said reflector at a predetermined distance from said light pipeentrance surface.

1. A light piping unit for use in supplying radiant energy to theinterior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombination: a fixture attached in pressure-fluid sealed relationshiprelative to said vessel wall peripherally of said wall aperture, saidfixture having an opening extending therethrough in alignment with saidwall aperture and said fixture opening defining an annular mountingsurface; a light pipe foRmed of a fiber optic material, said light pipebeing arranged to extend through said fixture opening and having aninner end portion arranged inwardly of said vessel to define a radiantenergy outlet surface, an outer end portion arranged outwardly of saidvessel to define a radiant energy entrance surface and an annularintegrally formed mounting surface complementary to said fixturemounting surface and maintained in pressure-fluid sealing engagementwith said fixture mounting surface by the difference between said vesseloperating and ambient pressures acting on said inner and outer endportions; a radiant energy source unit; and mounting means for removablysupporting said source unit outwardly of said vessel on one of saidfixture and said outer end portion of said light pipe whereby to applyradiant energy to said light pipe entrance surface for transfer intosaid vessel through said light pipe.
 2. A unit according to claim 1,wherein said mounting surfaces are of frusto-conical configuration andhave like cone angles.
 3. A unit according to claim 2, wherein each ofsaid cone angles is approximately 45*.
 4. A unit according to claim 1,wherein said source unit includes a housing carrying an electric lightbulb and a reflector for directing radiant energy from said bulb ontosaid light pipe entrance surface, and said mounting means releasablyclamping said housing to said outer end portion of said light pipe andincluding stop means engageable with said light pipe entrance surface toposition said bulb and said reflector at a predetermined distance fromsaid light pipe entrance surface.
 5. A unit according to claim 4,wherein said fixture includes an outer sleeve affixed to an outersurface of said vessel wall and an inner sleeve threadably affixed tosaid outer sleeve and defining said fixture mounting surface.
 6. A unitaccording to claim 1, wherein a tube is carried by said fixtureconcentrically outwardly of said light pipe, said source unit includes ahousing for carrying an electric light bulb and a reflector fordirecting radiant energy from said bulb onto said light pipe entrancesurface, and said mounting means releasably clamping said housing ontoan outer end of said tube and including stop means engageable with saidouter end of said tube to position said bulb and said reflector at apredetermined distance from said light pipe entrance surface.
 7. A unitaccording to claim 6, wherein said fixture includes a first part fixedto an inner surface of said vessel wall and defining said boundingsurface thereof, and a second part removably fixed to said first partfor engagement with said inner end portion of said light pipe forpositively maintaining said mounting surfaces seated in engagement, andan inner end of said tube extends inwardly through said wall apertureand is affixed to said first part.
 8. A unit according to claim 7,wherein said inner end portion of said light pipe is formed with anannular shoulder intermediate said mounting surface and said light pipeoutlet surface, and a deformable sealing device is clampingly securedagainst said shoulder by said second part.
 9. A unit according to claim1, wherein said source unit includes a housing carrying an electriclight bulb and a reflector for directing light from said bulb onto saidlight pipe entrance surface, said light pipe entrance surface isessentially of conically shaped configuration having an apex portionthereof extending towards said bulb, and said mounting means includesstop means cooperating with one of said fixture and said light pipe forpositioning said bulb and reflector at a predetermined distance fromsaid light pipe entrance surface.
 10. A light piping unit for use insupplying radiant energy to the interior of a pressure vessel having aninternal operating pressure differing from ambient pressure external tothe vessel, said vessel having an aperture formed in a wall thereof,which comprises in combination: a fixture attached to sAid vessel wallperipherally of said wall aperture, said fixture having an openingextending therethrough in alignment with said wall aperture; a radiantenergy source unit, said unit including a housing carrying an electriclight bulb and a reflector for directing radiant energy from said bulb;a light pipe fixed within said fixture opening, said light pipe havingan outer end portion defining a radiant energy entrance surface and aninner end portion defining a radiant energy outlet surface; and mountingmeans for removably mounting said housing on said outer end portion ofsaid light pipe, said mounting means including stop means engageablewith said light pipe entrance surface to position said bulb and saidreflector at a predetermined distance from said light pipe entrancesurface.
 11. A light piping unit for use in supplying radiant energy tothe interior of a pressure vessel having an internal operating pressurediffering from ambient pressure external to the vessel, said vesselhaving an aperture formed in a wall thereof, which comprises incombination: a fixture attached in pressure-fluid sealed relationshiprelative to said vessel wall peripherally of said wall aperture, saidfixture having an opening extending therethrough in alignment with saidaperture, and said fixture opening being stepped to define an annularmounting surface; a light pipe supported within said fixture opening,said light pipe having an outer end portion defining a radiant energyentrance surface and an inner end portion defining a radiant energyoutlet surface and an intermediate portion stepped to define anintegrally formed annular mounting surface facing towards and beingcomplementary to and maintained in pressure-fluid sealing engagementwith said fixture mounting surface by the difference between said vesseloperating and ambient pressures acting on said inner and outer endportions; a radiant energy source unit; and mounting means for removablysupporting said source unit outwardly of said vessel on one of saidfixture and said outer end portion of said light pipe whereby to applyradiant energy to said light entrance surface for transfer into saidvessel through said light pipe.
 12. A light piping unit for use insupplying radiant energy to the interior of a pressure vessel having aninternal operating pressure in excess of ambient pressure external tothe vessel, said vessel having an aperture formed in a wall thereof,which comprises in combination: a fixture having outer and innersleeves, said outer sleeve being attached in pressure-fluid sealedrelationship relative to said vessel wall peripherally of said wallaperture, said inner sleeve being threadably connected to said outersleeve and having a through opening arranged in alignment with saidvessel opening, said inner sleeve opening being stepped to define anannular mounting surface facing towards said vessel; a light pipesupported within said inner sleeve opening and having an integrallyformed annular mounting surface complementary to and disposed inpressure-fluid sealed engagement with said inner sleeve annular mountingsurface, said light pipe having an outer end portion defining a radiantenergy entrance surface and an inner end portion defining a radiantenergy outlet surface; a radiant energy source unit; and mounting meansfor removably supporting said source unit outwardly of said vessel onone of said fixture and said outer end portion of said light pipewhereby to apply radiant energy to said light pipe entrance surface fortransfer into said vessel through said light pipe.
 13. A light pipingunit for use in supplying radiant energy to the interior of a pressurevessel having an internal operating pressure differing from ambientpressure external to the vessel, said vessel having an aperture formedin a wall thereof, which comprises in combination: a fixture havingouter and inner sleeves, said outer sleeve being attached inpressure-fluid seaLed relationship relative to said vessel wallperipherally of said wall aperture, said inner sleeve being threadablyconnected to said outer sleeve and having a through opening arranged inalignment with said vessel opening, said inner sleeve opening beingstepped to define an annular mounting surface; a light pipe supportedwithin said inner sleeve opening and having an annular mounting surfacedisposed in pressure-fluid sealed engagement with said inner sleeveannular mounting surface, said light pipe having an outer end portiondefining a radiant energy entrance surface and an inner end portiondefining a radiant energy outlet surface; a radiant energy source unit,said source unit includes a housing carrying an electric light bulb anda reflector for directing radiant energy; and mounting means forremovably supporting said source unit outwardly of said vessel on saidlight pipe whereby to direct radiant energy to said light pipe entrancesurface for transfer into said vessel through said light pipe, saidmounting means releasably clamping said housing to said outer endportion of said light pipe and including stop means engageable with saidlight pipe entrance surface to position said bulb and said reflector ata predetermined distance from said light pipe entrance surface.